Transmission Of Toxoplasma Research Articles

Prevalence of toxoplasmosis among pregnant women in Najaf city

Toxoplasma gondii is globally distributed pathogen for human cause significant morbidity and mortality in developing fetus , in pregnant women toxoplasmosis is an important cause of abortions and stillbirth after primary infection . Therefore , the diagnosis of this infection is essential to prevent complications . This study was performed in order to evaluate the prevalence of toxoplasmosis in pregnant women and to study some factors that influence toxoplasmosis transmission . Among 260 sera samples tested using enzyme Linked immunosorbent assay(Elisa) . The seroprevalence of IgG which refer to chronic infection of Toxoplasma was (30.76 % )(80 out of 260 ) and IgM which refer to acute infection of Toxoplasma was (11.92%) (31 out of 260) . The present study demonstrated, that toxoplasmosis is more common among age group (25- 34 ) years ,and there is no statistically significant difference between of Toxoplasma infection and occupation of pregnant women , and there are significant role for the environmental and personal factors on Toxoplasma transmission , the study showed that the cats exposure woman were most affected by Toxoplasma ( 37. 5 %) and the pregnant women who not using disinfectant were more affected (42.51%) and the pregnant women who depending in their feeding on restaurant more frequent to infection with Toxoplasma (46.95%).

Seroprevalence of and Risk Factors forToxoplasma gondiiin the US Swine Herd Using Sera Collected During the National Animal Health Monitoring Survey (Swine 2006)

The United States Department of Agriculture (USDA) initiated the National Animal Health Monitoring System (NAHMS) in 1983 to collect, analyse and disseminate data on animal health, management and productivity in US domestic livestock populations, including swine. The programme includes an on-farm serological sampling component which can be used to monitor seroprevalence of various pathogens, including Toxoplasma gondii. The purpose of this study was to determine the seroprevalence of T. gondii in grower/finisher pigs using sera collected during NAHMS Swine 2006 and to determine farm level factors associated with differences in seroprevalence on farms where sera was collected during the Swine 2006 survey. Sera and data on management practices for this study were collected from 185 grower/finisher swine production sites located in 16 states accounting for > 90% of US swine production (Arkansas, Colorado, Iowa, Illinois, Indiana, Kansas, Michigan, Minnesota, Missouri, Nebraska, North Carolina, Ohio, Pennsylvania, South Dakota, Texas and Wisconsin). A total of 6238 sera were tested for T. gondii antibodies using a commercial ELISA assay (Vet. Parasitol.128, 2005, 177). Seroprevalence in this study, as determined by ELISA, was 2.6%, with a herd prevalence of 21.6% and a mean within-herd prevalence of 2.7%. Analysis of swine management practices indicated that rodent control methods and carcass disposal methods were associated with differences in the number of T. gondii positive samples on farm. These results are consistent with current epidemiological knowledge of the transmission of Toxoplasma on the farm (ingestion of organic matter containing oocysts, or ingestion of infected animal tissues). Production practices which eliminate these sources of exposure can reduce the risk of Toxoplasma infection in pigs, and reduce the likelihood of human infection from consumption of infected pork.

Surface Properties of Toxoplasma gondii Oocysts and Surrogate Microspheres

The physical properties that govern the waterborne transmission of Toxoplasma gondii oocysts from land to sea were evaluated and compared to the properties of carboxylated microspheres, which could serve as surrogates for T. gondii oocysts in transport and water treatment studies. The electrophoretic mobilities of T. gondii oocysts, lightly carboxylated Dragon Green microspheres, and heavily carboxylated Glacial Blue microspheres were determined in ultrapure water, artificial freshwater with and without dissolved organic carbon, artificial estuarine water, and artificial seawater. The surface wettabilities of oocysts and microspheres were determined using a water contact angle approach. Toxoplasma gondii oocysts and microspheres were negatively charged in freshwater solutions, but their charges were neutralized in estuarine water and seawater. Oocysts, Glacial Blue microspheres, and unwashed Dragon Green microspheres had low contact angles, indicating that they were hydrophilic; however, once washed, Dragon Green microspheres became markedly hydrophobic. The hydrophilic nature and negative charge of T. gondii oocysts in freshwater could facilitate widespread contamination of waterways. The loss of charge observed in saline waters may lead to flocculation and subsequent accumulation of T. gondii oocysts in locations where freshwater and marine water mix, indicating a high risk of exposure for humans and wildlife in estuarine habitats with this zoonotic pathogen. While microspheres did not have surface properties identical to those of T. gondii, similar properties shared between each microsphere type and oocysts suggest that their joint application in transport and fate studies could provide a range of transport potentials in which oocysts are likely to behave.

The roles of cats and dogs in the transmission of Toxoplasma infection in Kuna and Embera children in eastern Panama

To examine the relationship between antibody status and various hypothesized risk factors for Toxoplasma gondii infection among two different Amerindian populations in eastern Panama. Following up on earlier research that we conducted, we now explore the role of dogs in the natural transmission of Toxoplasma, the role that dogs play in promoting transmission, the interactive effect of cats and dogs, and the accessibility of infective material to children. In 1991, 10 Panamanian medical students conducted interviews and took blood samples from 760 Kuna and Embera children aged 2 through 12 years in the Upper Bayano River Basin and the San Blas Islands. Serologic assays were performed using direct agglutination. The data analyses in the 1990s included univariate, bivariate, and multivariate analyses, without regard to data on dogs. Further bivariate and multivariate analyses were performed in 2003 to examine the contribution of dogs. In communities with high Toxoplasma antibody prevalence in children, logistic regression suggested that the factors predictive of antibody presence were: compacted soil floors of huts (P = 0.001), having a dog (P = 0.038), and the interviewer seeing a cat in the house (P = 0.049). Our results suggest that the villagers' dogs play a significant role in facilitating the transmission of Toxoplasma gondii to humans, most often in the presence of cats in the houses, and only in those communities with higher Toxoplasma seroprevalence in children. Dogs may act as mechanical vectors, by rolling in foul-smelling substances and by ingesting fecal material. In areas of high Toxoplasma prevalence in children and where dogs and cats are plentiful, immunocompromised individuals and pregnant women should be warned of the possibility of acquiring Toxoplasma gondii from dogs as well as from soil contaminated by cats. People should be encouraged to wash their hands after contact with soil, dogs, or cats as well as before eating.

Congenital toxoplasmosis: eye manifestations in infants and children.

The eye manifestations of congenital toxoplasmosis were investigated in 38 infants and children. Diagnosis of the congenital ocular lesions was established clinically, using also X-ray, computed tomography and ultrasonography, and confirmed by two immunodiagnostic techniques. Infants and children were examined when one or more characteristic manifestations of ophthalmic disorders were present. Typical symptoms and signs can present at birth or appear later in life. The multiplicity of clinical manifestations is characteristic of the disease. The most common symptom was chorioretinitis (92%), associated in 71% of the cases with other ocular lesions, and the second most common symptom was microphthalmia and strabismus. The inflammatory process also involved the anterior segment of the eye: iridocyclitis, cataract, glaucoma. Other rare findings were hydrocephalus, calcification in the brain, paresis, epilepsy and diminished visual acuity. The study showed that transplacental transmission of Toxoplasma to the fetus can have severe clinical consequences and terminate in fatal ocular impairment.

Effect of prenatal treatment on mother to child transmission of Toxoplasma gondii: retrospective cohort study of 554 mother-child pairs in Lyon, France.

The aim of prenatal serological screening for toxoplasmosis is to identify and treat maternal infection as soon as possible in order to prevent transmission of the parasite to the fetus. However, despite widespread provision of prenatal toxoplasma screening across Europe, the effectiveness of prenatal treatment is uncertain. The study aimed to determine the effect of the timing and type of prenatal treatment on mother to child transmission of Toxoplasma gondii. A cohort of 554 infected pregnant women were identified in Lyon, France between 1987 and 1995 and their children were followed to determine congenital infection status. We determined the effect of prenatal treatment on transmission by examining the effect of the delay between maternal seroconversion and start of treatment. We also compared the effect of the type of treatment and no treatment on the risk of mother to child transmission. Analyses were adjusted for gestation at maternal seroconversion. Compared to treatment within 4 weeks from seroconversion, the adjusted odds ratios (OR) for mother to child transmission after a treatment delay of 4-7 weeks was 1.29 (95% CI : 0.61, 2.73) and after more than 8 weeks, 1.44 (95% CI : 0.60, 3.31). The adjusted OR associated with spiramycin alone compared with pyrimethamine-sulfadiazine treatment was 0.91 (95% CI : 0.45, 1.84) and the OR for no treatment compared with pyrimethamine-sulfadiazine treatment was 1.06 (95% CI : 0.37, 3.03). The authors hypothesize that the absence of an effect of prenatal treatment is due to transmission before the start of treatment.

Epidemiological importance of animals in the transmission of Toxoplasma

Epidemiological importance of animals in the transmission of Toxoplasma

Vertical transmission of toxoplasma by human immunodeficiency virus-infected women: Minkoff H.; Remington J.S.; Holman S.; Ramirez R.; Goodwin S.; Landesman S. USA Am J Obstet Gynecol 1997 176/3 (555–559)

Vertical transmission of toxoplasma by human immunodeficiency virus-infected women: Minkoff H.; Remington J.S.; Holman S.; Ramirez R.; Goodwin S.; Landesman S. USA Am J Obstet Gynecol 1997 176/3 (555–559)

Vertical transmission of toxoplasma by human immunodeficiency virus–infected women

OBJECTIVE: Our goal was to determine the frequency of mother-to-child transmission of Toxoplasma gondii from human immunodeficiency virus–infected mothers who are also chronically infected with T. gondii. STUDY DESIGN: One hundred thirty-eight women were entered into a prospective study of human immunodeficiency virus infection in pregnancy. The women were seen at enrollment, during the third, sixth, and eighth months of pregnancy (except those enrolled later in pregnancy or at delivery), at 2 and 6 months post partum, and at 6-month intervals thereafter through 4 years after delivery. Standardized interviews and physical examinations were performed, and blood was drawn at each visit. Toxoplasma serologic testing was performed on the sample drawn earliest in pregnancy; the Sabin-Feldman dye test for immunoglobulin G antibodies and enzyme-linked immunoassays for immunoglobulins M, A, and E were used. Univariate analysis for categoric variables was performed with χ 2and two-tailed Fisher exact tests, and for continuous variables the Student t test was used. Statistical Analysis System procedures were followed. RESULTS: Twenty-eight of 138 (20.2%) women who had positive test results for human immunodeficiency virus had positive findings of the Sabin-Feldman dye test. Serologic status for T. gondii did not correlate with age, immune status, parity, or drug use. One of 27 children born to women who were seropositive for both human immunodeficiency virus and T. gondii (one child's serologic status for T. gondii was unknown) had Sabin-Feldman dye test antibodies beyond age 6 months (3.7%, 95% confidence interval 0.09% to 18.9%). Among the cohort of human immunodeficiency virus–infected mothers the rate of mother-to-child human immunodeficiency virus transmission did not vary with maternal Toxoplasma status. However, with sample sizes of 28 and 110, respectively, for the mothers who were T. gondii seropositive and seronegative, the power to detect a difference in the human immunodeficiency virus transmission rate between these groups would be relatively small. CONCLUSIONS: Transmission of T. gondii from a chronically infected mother can occur in the setting of a human immunodeficiency virus infection, but this is not a common phenomenon. In a small cohort of human immunodeficiency virus–infected women we did not observe its occurrence among those without severe immunocompromise.(Am J Obstet Gynecol 1997;167:555-9.)

Prophylaxis of congenital toxoplasmosis. Effects of spiramycin on placental infection.

The results of parasitological investigation of the placenta for toxoplasma in 223 cases with documented congenital toxoplasmosis were analysed according to whether the mother had been treated, or not, with spiramycin during pregnancy. The investigation was negative in 10-11% of the cases when the mother had not been treated or had been inadequately treated; in 25% of the cases with a treatment of 3 g spiramycin day; and in 50% with spiramycin plus the combination of pyrimethamine with sulphonamide. This series is compared with a previous group of 321 women whose placental investigation was negative in 50% of untreated cases and 81% of treated women. The treatment categories are not directly comparable, because it is not possible to have a randomly assigned 'no treatment' group, for ethical reasons. Correlation between spiramycin treatment and negative results of mouse inoculation of placental material suggests that spiramycin might decrease the risk of materno-fetal transmission of toxoplasma by reducing the severity and duration of toxoplasmic placentitis. Current use of spiramycin in infected pregnant women is recommended because of its activity and lack of side effects. The dosage must not be lower than 3 g/day. Additional pyrimethamine plus sulphonamide should be restricted to selected cases with fetal abnormality diagnosed during pregnancy. Some data on pharmacology of spiramycin in mothers, placentas and fetuses are reviewed. They suggest that monitoring of maternal serum antibody titres for a dosage more adapted to individual cases may be desirable.

Epidemiology of toxoplasmosis among pregnant women in the Paris area.

A survey was performed using a sample of pregnant women selected at one of the biggest test centres in the Paris area. These women were serologically screened for toxoplasmosis between October 1981 and September 1983 (according to the prevention protocol for congenital toxoplasmosis established by the French health ministry). The prevalence rate of specific antibodies for toxoplasmosis was estimated from the 1074 women who were tested for the first time during the study. The prevalence rate among pregnant women in the Paris area was derived by direct standardization according to age and geographical origin. A standardized prevalence rate of 71% +/- 4% among French women, of 51.4% +/- 5% among immigrant women and a global adjusted prevalence rate of 67.3% +/- 3% for pregnant women in the Paris area was found. An incidence rate of 1.6% was estimated for the 2216 non-immune pregnant women included in the sample. There is no significant difference between the probabilities of seroconversion among French and immigrant women (2.3% +/- 1% and 1.6% +/- 0.8% respectively). Comparison of the data with previous study results show a decrease in the prevalence rate of specific antibodies for toxoplasmosis in the Paris area over the last 20 years that cannot be explained by changes in age and geographical origin. No data were available to support an aetiological hypothesis for a decrease in toxoplasma transmission to humans. Since immigration and a decrease in toxoplasma transmission to humans has led to a larger population of women at risk of infection during pregnancy in France, it is therefore important to perform studies to investigate risk factors and markers of acquired toxoplasmosis during pregnancy in order to improve the prevention of congenital toxoplasmosis.

Toxoplasma antibody titers in renal transplant recipients. Pretransplant evaluation and posttransplant follow-up of 73 patients.

In 73 consecutive kidney transplant recipients, anti-Toxoplasma antibodies were determined before transplantation and during a 3-year follow-up after transplantation. In 9 patients, antibody titers increased significantly after transplantation. Antibody titers to various viral antigens determined in parallel remained unchanged, suggesting that the anti-Toxoplasma antibody increase was not due to polyclonal nonspecific stimulation. In 2 of the 24 pretransplant seronegative patients, acquired toxoplasmosis was diagnosed serologically after transplantation, with the observation of a strong IgM and IgG antibody response. The incidence of toxoplasmosis in this group of patients was not found to be significantly different from that in a normal population, suggesting that transmission of Toxoplasma from the transplanted kidney may not be a significant mode of contamination. Among the 49 patients who were seropositive before transplantation, reactivation of toxoplasmosis was suspected in 7 cases on the basis of a significant increase in IgG antibodies. Reactivation occurred more frequently in patients treated with azathioprine and antithymocyte globulin, and a direct relationship between administration of steroids and antibody increase was demonstrated in three patients. Although toxoplasmosis has occasionally been reported as a major infectious problem in kidney transplant recipients, our clinical and serological data show that the potential risk of developing Toxoplasma infection is low since none of the patients with either acquired or reactivated toxoplasmosis developed clinical disease.

The epidemiology of ovine toxoplasmosis. III. Observations on outbreaks of clinical toxoplasmosis in relation to possible mechanisms of transmission

The proceeding paper in this series (Blewett & Watson, 1983) described three simple models for the transmission of Toxoplasma in breeding flocks and each model attributed distinctive characteristics to outbreaks of ovine toxoplasmosis. These characteristics referred to such readily observed features of clinical outbreaks as the recurrence of clinical toxoplasmosis in successive lambing seasons, the distribution of losses within the flock, the introduction of bought-in replacement ewes and the range of clinical signs at lambing. This paper tests the three models described earlier by comparing their predictions with the observed properties of outbreaks of clinical ovine toxoplasmosis.

Seroepidemiological survey of toxoplasmosis in La Guadeloupe, French West Indies.

A random survey of 1% of the total population of La Guadeloupe, French West Indies, for toxoplasmosis was carried out. Blood specimens from 3,238 individuals were collected on filter paper strips and tested for Toxoplasma antibodies by the fluorescent antibody technique. Sixty percent were positive. A gradual increase in positivity with increasing age, and high prevalence in children (50% in the 6- to 10-year age group) were observed. No differences were found among the different ethnic groups, nor among persons in different occupations. Economic status showed a highly negative correlation with antibody prevalence rates. The infection rate was not higher in individuals who consumed raw or undercooked meat, and no differences in antibody prevalence related to the sources of meat were observed. The seropositivity rates varied over a wide range (40-76%) according to the locality; higher Toxoplasma antibody rates were found in areas with higher rainfall, and toxoplasmosis prevalence rates correlated positively with mean annual rainfall but not with altitude or with rural or urban residence. A significant difference was observed between seropositivity rates when people living in houses with or without cats were compared. A higher prevalence of hookworm and Strongyloides infections--considered as evidence of closer contact with moist soil--were found in children with Toxoplasma antibodies than in age-adjusted control children without such antibodies. These results provide evidence that meat plays a negligible role in the transmission of Toxoplasma to man, and support the hypothesis that oocysts shed in cat feces are the almost exclusive mode of human infection in Guadeloupe.

Probable Transmission of Toxoplasma gondii by Organ Transplantation

Two heart transplant recipients developed toxoplasmosis shortly after surgery. As neither recipient had serologic evidence of exposure to Toxoplasma gondii before transplantation, infection was acquired from an exogenous source. Of the possible modes of transmission of Toxoplasma to the recipients, infection by the oral route or through transfusion of blood or blood products seems remote. Since both heart donors had serologic evidence of recently acquired toxoplasma infection at the time of transplantation and the myocardium is known to be infected with the organism during acute infection, we considered these facts to be a strong implication that the donors' hearts were the most likely source of toxoplasma infection in the recipients.

Transmission of Toxoplasma.

Toxoplasma gondii , a ubiquitous parasite of mammals and birds in nature, is one of the most common infections of humans the world over. In the United States alone, at least 66 million persons are infected by this protozoan. Although recognized as a cause of disease in humans for more than 50 years, the probable means whereby this parasite is transmitted has only recently been elucidated. In the life cycle of Toxoplasma , there are three forms of the parasite: the trophozoite or proliferative form, the tissue cyst, and the oocyst. The trophozoite is an obligate intracellular form that invades all types of mammalian cells and can be seen during the acute stage of the infection. The tissue cyst develops in host cells from trophozoites and may vary in size from those containing only a few organisms to those containing several thousand. Such tissue cysts may persist in any tissue and are

The possibility of transmission of toxoplasma by means of blood transfusions

Das Vorkommen von Toxoplasmen im Blut von Blutspendern ist beschrieben worden. In eigenen Versuchen konnte nachgewiesen werden, das die Parasiten in Blutkonserven mehrere Wochen uberleben konnen. Aus Blutproben von 1500 untersuchten Spendern konnten in keinem Falle Toxoplasmen im Tierversuch angezuchter werden. Bei 75 bis 80% der Personen waren Toxoplasma-Antikorper nachweisbar, die bei 4,2%Sabin-Feldman-Test (SFT)/Komplementbindungsreaktion (KBR)-Werte von ≧1∶1000/≧1∶10 aufwiesen. Der Bluttransfusion scheint im Hinblick auf die Ubertragung der Toxoplasma-Infektion keine epidemiologische Bedeutung zuzukommen.

Further observations on the epidemiology of ovine Toxoplasma infection.

SummaryThis paper records a seven year follow‐up epidemiological investigation in the surviving offspring of a flock of ewes which had experienced an outbreak of overt congenital toxoplasmosis. The following observations were made:Fifty‐one percent of the offspring of dye test (D.T.) positive ewes developed antibodies to Toxoplasma.The duration and level of this antibody response varied considerably: in some sheep it was persistent and in others it fluctuated between negativity and positivity, and in one year there was a general and pronounced rise in D.T. titres.Fourteen percent of the offspring of dams with a D.T. titre of 1:64 became sero‐positive, whereas 90% of the offspring of ewes with D.T. titres of 1:1,024 or greater became sero‐positive.No congenital transmission of Toxoplasma occurred when the D.T. positive offspring were mated.All offspring born from D.T. negative ewes and running in contact with D.T. positive sheep remained sero‐negative over a 6 year period.Latent congenital Toxoplasma infection persisted in 93% of D.T. positive offspring for up to 7 years.

Advances in the biology of sporozoa.

Progress in the understanding of the sporozoa stemmed from new concepts and new measurements, often using refined techniques. New concepts developed from linking knowledge about the cyst-related transmission of Toxoplasma to oocyst-related transmission of the coccidia. It is now apparent that both oocyst and tissue cyst transmission occur in Toxoplasma, Sarcocystis, Hammondia n.g., Isospora and perhaps Atoxoplasma. It is likely that we know the complete cycles of Toxoplasma and Sarcocystis and some progress has been made towards understanding those of Besnoitia and Frenkelia. Our present knowledge is sufficient to propose a new classification of some of the higher coccidia (Table 5), and to devise keys for the determination of cysts and oocysts (Tables 2, 4). Additional terminology is listed (Table 1).

Toxoplasma in and around Us

Toxoplasma infections are quite prevalent, with 1/4 to /2 of the adults in the U.S. and elsewhere asymptomatically infected. Toxoplasma was first discovered not in sick humans or livestock, but in laboratory animals! Not even in conventional rats and mice, but in gondis (Ctenodactylus gondi), small cricetid rodents from North Africa, which were used at the Pasteur Institute of Tunis for leishmaniasis research (Nicolle and Manceaux 1908). The gondis came from the foothills and mountains of southern Tunisia, and it was soon realized that they were not infected in nature, but that they became infected in the laboratory (Chatton and Blanc 1917). Ticks, chiggers, fleas, and black flies were examined as possible vectors, but inconclusively. Almost at the same time as in Tunisia, Toxoplasma was described from a laboratory rabbit from Sao Paulo, Brazil (Splendore, 1908), early suggesting its worldwide distribution. Little was discovered about the transmission of Toxoplasma, however, through the subsequent years until the late 1930's and 1940's when Toxoplasma was found in newborn babies in the U.S. by Wolf and Cowan (1937) and Sabin (1942). Although transplacental transmission was proven in man and animals, this mode of transmission turned out to be rare, at least in humans, although a number of epidemic outbreaks have been described from sheep (Watson and Beverley 1971). After the development of a sensitive serologic test by Sabin and Feldman (1948), Toxoplasma antibody was fond earthwide, especially in areas with moist and warm climates. Human Disease due to Toxoplasma